Field of the Invention
The present invention relates to wireless communication, and more particularly, to a method and apparatus for determining a size of a transport block in a wireless communication system.
Related Art
A system configured in a next-generation wireless communication system may be different from that of the conventional wireless communication system. For example, a machine type communication (MTC) terminal may be used in the next-generation wireless communication system. The MTC terminal implies a low cost/low specification terminal which primarily aims at data communication, such as reading a meter, measuring a water level, utilizing a surveillance camera, inventory reporting of a vending machine, etc.
Alternatively, the next-generation wireless communication system may deploy more small cells to increase a frequency reuse of the entire system, thereby being able to increase a throughput of the entire system. In addition, the next-generation wireless communication system uses coordinated multiple point (CoMP) transmission and reception as an effort for increasing a cell coverage and for more effectively utilizing resources.
The next-generation wireless communication system may require channel state information (CSI) reporting for more cells/transmission points (TPs). As a result, the CSI may need to be transmitted in a greater amount in comparison with the conventional case.
In such a situation, if data and CSI are transmitted simultaneously through a data channel, resources occupied by the CSI are increased in the data channel. As a result, resources that can be used for transmission of data in the data channel are decreased.
Meanwhile, the data is transmitted in unit of transport block (TB), and one TB or two TBs may be transmitted in one data channel according to whether spatial multiplexing using multiple layers is applied.
Conventionally, a TB size is determined according to an amount of resources allocated to the data channel and a modulation and coding scheme (MCS) in use. However, an amount of CSI transmitted together with data through the data channel is not particularly considered in the conventional wireless communication system. Accordingly, since the amount of the CSI may be increased in the next-generation wireless communication system, a method of determining a TB size by considering this is necessary.
In addition, data may be transmitted through a plurality of subframes according to a scheduling scheme. In this case, it may be ineffective to determine the TB size by considering only an amount of resources allocated in one subframe.
In addition, if acknowledgement (ACK)/not-acknowledgement (NACK) must also be transmitted in a situation where data and control information are transmitted together through a data channel, for reliable ACK/NACK transmission, it may be necessary to determine a method of configuring a resource to which the ACK/NACK is mapped and determine which channel is used to transmit the ACK/NACK between the data channel and a control channel.